Interview with K Canfell - Part II
Quote this article as:
K Canfell (January 2024). Interview with Karen Canfell (Part II). www.HPVWorld.com, 260
In the context of the WHO cervical cancer elimination campaign (90% vaccination, 70% HPV screening, 90% treatment), which are important proposals related to HPV vaccination: required levels of female vaccine coverage? Added value of including routine vaccination of boys? Predictions on the protection afforded by one-dose vaccination?
The WHO 90-70-90 targets define 2030 goals for action across the three pillars of cervical cancer control. For vaccination, the key target relates to girls to the age of 15 years – that 90% worldwide are vaccinated by 2030. The vaccination of boys can also be considered if cost-effective and if there is a sufficient and an affordable vaccine supply in a country. One-dose vaccination should facilitate this more and more over time. In 2022, WHO’s Strategic Advisory Group of Experts (SAGE) published a position statement that found that 'current evidence suggests that a single dose has comparable efficacy and duration of protection as a 2-dose schedule'1. This will be an incredibly important facilitator of higher coverage, and an increasing number of countries at various income levels have now moved to adopt this approach.
In this same context, what are the most important issues in delivering high-quality screening? The added value of transitioning to HPV primary screening? The value of other screening alternatives (VIA, cytology)? How to screen vaccinated cohorts?
From a screening perspective, the most important development in recent years has been the new WHO guideline for screening and treatment of cervical pre-cancer lesions for cervical cancer prevention. This was supported by extensive evidence review and modelling by our team at the Daffodil Centre. We modelled the comparative benefits, harms and costs for women in the general population and women living with HIV2,3, and this supported the WHO’s key recommendation to use “HPV DNA detection as the primary screening test rather than VIA or cytology in screening and treatment approaches, among both the general population of women and women living with HIV”2,3.
The WHO Cervical Cancer Elimination Modelling Consortium (CCEMC) modelling found that if WHO coverage targets of 90-70-90 for vaccination, screening and treatment could be achieved, over 74 million cases and 62 million deaths could be averted in low- and middle-income countries, with all countries achieving elimination at 4 cases per 100,000 over the course of a century, meaning cervical cancer would be considered to be controlled as a public health problem4.
Where is Australia in the elimination path and what is the prediction for the current decade?
Australia has implemented many public health transitions over the years, and the cumulative effect positions the country to be at the forefront of the elimination of cervical cancer. Australia has had a national immunisation program for decades, which has included vaccines administered in school and preschool settings. In 2007 an initial two-year catch-up HPV vaccination for girls and women up to age 26 in community and primary care clinics was conducted; in 2013 boys were included (after cost-effectiveness assessment); and in 2018 there was a switch to a two-dose schedule with nonavalent vaccine5. In 2020, completed course vaccination coverage in Australia by age 15 was 81% in females and 77% in males although it was lower in Indigenous adolescents (75% in females; 68% in males). However, coverage has increased since vaccine introduction and an incredibly important development was the recommendation for 1-dose vaccination which Australia adopted at the end of 2022, following the WHO SAGE position paper1.
Australia already has very low cervical cancer incidence and mortality rates, due mainly to the success of the organised cervical screening program, first introduced in 1991. The shift from Pap test screening to HPV-based screening, from 2017 onwards, is set to further reduce cervical cancer rates by up to 25%, putting Australia on a path to cervical cancer elimination by 2035. About 65% of Australian women were up to date with their 5-yearly HPV screening at the end of 2020. Another major development in 2022 was the change to allow universal access to HPV self-collection, and increased coverage for cervical screening will be greatly facilitated by community-driven models using self-collected HPV testing.
There have been well-documented drops in HPV infections, cervical precancerous abnormalities and genital warts. In 2018-19 our team predicted that Australia is on track to eliminate cervical cancer, achieving rates lower than 4 per 100,000 women per annum in the period 2028-356. The current focus is to make sure we do this equitably, and a National Strategy for the Elimination of Cervical Cancer has been developed to ensure this. The vision is “an Australia where preventable cervical cancer is a disease of the past, in which Australia’s diverse communities have equitable access to information and to culturally safe and inclusive vaccination, screening and treatment services.”
In closing, I think a major message here is that the knowledge of HPV natural history which sits behind the development of the effective primary and secondary interventions available to us (prophylactic HPV vaccination and HPV-based cervical screening) also underpins the development of accurate and large-scale modelling platforms for country-level and global predictions. If done well, comprehensive and well-validated models can help inspire action by providing the information that policymakers and advocates need, about the impact and investment case for cervical cancer elimination..
References
1. World Health Organization (WHO). Human papillomavirus vaccines: WHO position paper, December 2022. Available at: https://www.who.int/publications/i/item/who-wer9750-645-672
2. Simms KT, Keane A, Nguyen DTN, Caruana M, Hall MT, Lui G, et al. Benefits, harms and cost-effectiveness of cervical screening, triage and treatment strategies for women in the general population. Nat Med. 2023;29(12):3050-3058. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10719104/
3. Hall MT, Simms KT, Murray JM, Keane A, Nguyen DTN, Caruana M, et al. Benefits and harms of cervical screening, triage and treatment strategies in women living with HIV. Nat Med. 2023;29(12):3059-3066. Available at: https://pubmed.ncbi.nlm.nih.gov/38087116/
4. Canfell K, Kim JJ, Brisson M, et al. Mortality impact of achieving WHO cervical cancer elimination targets: a comparative modelling analysis in 78 low-income and lower-middle-income countries. Lancet. 2020;395(10224):591-603. Available at: https://doi.org/10.1016/s0140-6736(20)30157-4
5. D Machalek & C Davies (January 2023). Australia’s HPV Vaccination Program: 15 years of success. www.HPVWorld.com, 222. Available at: https://www.hpvworld.com/articles/australias-hpv-vaccination-program-15-years-of-success/
6. Hall MT, Simms KT, Lew JB, et al. The projected timeframe until cervical cancer elimination in Australia: a modelling study. Lancet Public Health. 2019;4(1):e19-e27. Available at: https://doi.org/10.1016/s2468-2667(18)30183-x
This article is included in the HPW Special Issue The role of modelling in informing policy and planning for prevention and control of HPV-related cancers
Scientific coordinators:
Karen Canfell, Adam Keane, Diep TN Nguyen, Michaela T Hall, James Killen, Xavier Bosch
HPW editors:
Marisa Mena, Patricia Guijarro, Paula Peremiquel
On behalf of the editorial team, we would like to thank all the authors who contributed to this special issue of HPW
OTHER ARTICLES IN THIS HPW SPECIAL ISSUE:
Interview with K Canfell-Part I
EA Burger, JJ Kim. Planning for cervical cancer elimination: The role of simulation modelling
J Berkhof. IARC Handbook on cervical cancer screening: value of this evidence synthesis for modelling
M Smith, EA Burger, I de Kok. How does COVID-19 impact cervical screening?
YL Woo, M Saville, A Keane. The road to cervical cancer elimination in Malaysia
M Jit, JJ Kim, M Brisson. Modelling 1-dose HPV vaccination
N Campos, L Bruni, JJ Kim, M Schiffman. Refining health decision models to evaluate novel screening strategies in low-resource settings
C Hathaway, G Liu, RV Barnabas. Understanding HPV prevention and control in women living with HIV
I Man, I Baussano. Building resilient cancer prevention through gender-neutral HPV vaccination
